The present invention relates to a disc drive slider microactuator and sensor, and more particularly to a silicon-based thin film electromagnetic transducer providing improved actuation force and sensor sensitivity in a disc drive system.
The density, or radial spacing, between concentric data tracks on magnetic discs continues to increase, requiring greater precision of head positioning. Conventionally, head positioning is accomplished by operating an actuator arm with a large-scale actuator motor, such as a voice coil motor, to position a head on a gimbal at the end of the actuator arm. The large-scale motor lacks sufficient resolution to effectively accommodate high track-density discs. Thus, a high resolution head positioning mechanism, or microactuator, is necessary to accommodate the more densely spaced tracks.
Various microactuator locations and designs have been considered to achieve high resolution head positioning. One promising design involves inserting a silicon-based thin film structure between the suspension and the slider in a disc drive assembly. The microactuator includes, for example, an electromagnetic transducer having magnetic core materials forming a stator and a rotor, with conductive coils wrapped around the stator core in a solenoid-type or planar-type configuration. One of the major technical challenges in implementing such a microactuator is to provide sufficiently large actuation force to overcome friction forces and spring bias forces to drive the head at a speed high enough to accommodate the required bandwidth. Such a design must be realized in a relatively small wafer area, to keep costs reasonable and to allow easy integration into the disc drive design. It would also be useful for the microactuator to include a position sensor to discern the relative position of the movable portion of the microactuator.
Therefore, there is a need in the art for a microactuator design providing large actuation force with reasonable power consumption and within a reasonable wafer area to microposition a transducing head at a speed that accommodates the high bandwidth required by high performance disc drives, and further for a microactuator design that includes the capability to sense the position of the movable portion of the microactuator.